At present, in order to solve noise pollution, many experts are studying methods to improve the noise reduction performance of sound barriers and acoustic devices. However,the development of sound-absorbing structures under external noise environments with multiple frequencies has not made significant progress.To improve the sound absorption performance (SAP) and sound insulation performance (SIP) of structures, a novel cavity-imitating sound-absorbing structure model was established based on the multi-cavity resonance structure of conches. By performing experiments with an impedance tube and finite element simulation, the internal design of, and experimental results from a conch-imitating cavity structure (CICS) were analysed. In addition, a variety of structural parameters were investigated and the application of the sound absorber was analyzed. The analytical results showed that the CICS exhibits excellent SAP at low and intermediate frequencies. The peak frequency and sound absorption bandwidth can be changed and optimised by adjusting the structural parameters. The results show that the structure can effectively improve the sound absorption and insulation performance of the sound barrier to achieve the purpose of improving the acoustic performance, and proposes a new solution for the realisation of sound absorption and noise reduction in a multi-noise environment.
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http://dx.doi.org/10.1177/00368504221075167 | DOI Listing |
JASA Express Lett
January 2025
Key Laboratory of Noise and Vibration Research, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190,
Through non-dimensional analysis of the nonlinear sound absorption characteristics of rigid-porous layers, the results indicate that the nonlinear sound absorption trend of a porous layer (PL) at high sound pressure levels (SPLs) mainly depends on the state of flow resistance matching. When a PL is in an under-matched state, the sound absorption coefficient (SAC) will initially rise to a maximum and then gradually decline as SPL increases. Comparatively, when it is in an over-matched state, the SAC will decrease monotonically.
View Article and Find Full Text PDFArch Toxicol
January 2025
Cosmetics Europe, Brussels, Belgium.
Grouping of chemicals has been proposed as a strategy to speed up the screening and identification of potential substances of concern among the broad chemical universe under REACH. Such grouping is usually based on shared structural features and should only be used for the prioritization objectives. However, additional considerations (as well as structural similarity) are needed, e.
View Article and Find Full Text PDFSci Rep
December 2024
Faculty of Mechanical Engineering, Department of Machining, Assembly and Engineering Metrology, VSB-Technical University of Ostrava, Ostrava-Poruba, 708 00, Czech Republic.
The aim of this work is to investigate the sound absorption properties of open-porous polyamide 12 (PA12) structures produced using Selective Laser Sintering (SLS) technology. The examined 3D-printed samples, fabricated with hexagonal prism lattice structures, featured varying thicknesses, cell sizes, and orientations. Additionally, some samples were produced with an outer shell to evaluate its impact on sound absorption.
View Article and Find Full Text PDFMacromol Rapid Commun
December 2024
Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1 Panepistimiou Avenue Nicosia, Aglantzia, 2109, Cyprus.
Sound absorption plays a crucial role in addressing noise pollution that may cause harm to both human health and wildlife. To tackle this environmental issue, the implementation of natural-based sound absorbing materials attracts considerable attention in the last few years. In this study, sound absorbing, eco-friendly composites are produced by combining a 3D natural sponge namely Luffa Cylindrica (LC) with cellulose acetate (CA) microfibrous layers that are fabricated through electrospinning.
View Article and Find Full Text PDFJ Dairy Sci
December 2024
Department of Animal Science, University of California, Davis, Davis, CA 95616.
Several metrics have developed for combining the warming effects of various greenhouse gases (GHG). The metric used can affect the life cycle assessment and comparison of dairy production systems due to the weighting placed on long- versus short-lived gases in the atmosphere. Global warming potential with a time horizon of 100 years (GWP-100) has become the standard but metrics are also available for other time horizons.
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